As far as I know, there are only three types of bear can on the market: Bearikade (2 sizes), Bear Vault, and Garcia.
There is only one long haul on the JMT: Vermillion Valley Resort (or Muir Trail Ranch) to Whitney, which is around 120 miles.
If you’ve not already made an investment, then perhaps the best option is to get a relatively small, cheap can (Bear Vault), but pack VERY CAREFULLY for that one haul. Hikers are used to looking at calories per unit weight. When packing a bear can, you have to think about calories per unit of volume. For example, Cheetos have plenty of calories by weight, but horrible calories by volume. On the other hand, tortillas and rice are both very compact.
Here is one site that talks about packing a bear can efficiently:
http://www.sierrawildbear.gov/foodstorage/packingabearcanister.htm
There is another site, which I can’t find right now, that is written by an absolute psycho on the subject of dense packing— which is EXACTLY the kind of person I’d want to hear from in this situation 
Eric